1. Field of the Invention
The invention disclosed herein related to data processing devices and more particularly relates to post processing devices for the detection of typographical errors resulting from the use of keyboards and the like.
2. Description of the Prior Art
One of the more burdensome problems to principals in the word processing industry is the necessity for retyping of documents due to spelling typographical errors. The invention of typewriters with electronic and/or magnetic memories has aided in the solution to this problem by permitting the typist to only retype the error words while the remainder of the text is played out automatically at high speed. However, the likelihood of spelling error free output from these devices is only as good as the spelling ability of the typist and the likelihood that error words will be overlooked is high.
A significant advance in the art of misspelling detection has been contributed by W. S. Rosenbaum in U.S. Pat. No. 3,995,254, issued Nov. 30, 1976, entitled "Digital Reference Matrix to Word Verification", and assigned to the same assignee as the present application. A digital reference matrix is disclosed therein which provides for compact storage of a dictionary of correctly spelled words to be used to verify input words from a keyboard, character recognition machine or voice analyzer. A vector representation for each word in the dictionary is calculated in the form of a magnitude and unique angle combination. These representations are stored in a memory. Input words to be checked for spelling errors then undergo a magnitude and angle calculation, the results of which are compared to the dictionary/memory. An output signal is generated indicating the result of the compare. While Rosenbaum provides an accurate means for verifying the spelling of input words, it does not provide for efficient operation in word processing systems where throughput is the paramount requirement. This lack of efficiency is due to the disruption of the operator's typing rhythm caused by signalling each time a typed word does not appear in the dictionary.